Ok, I have one last thing to say.
Changing 270 to 271 does work and the ship won't technically go off screen even though it does drift down slightly, but why would you even need to do that?
I completely don't understand this style of programming and yes the manual is very confusing. We shouldn't have to test every little thing.
Basically the way the in between function is coded is ridiculous because it forces you to use an extra number and behavior I didn't want (it should work at just 270 without having to go into 270.353535 or whatever).
And when one states in the manual something is in a 45 degree quadrant, that should mean 0 to 45 degrees.
So I think this is sloppy software design.
And this is the only bug I found in my game, which seems to be unfixable because of C2 design.